This invention is directed to a unique device and method for penetrating body tissues for medical purposes such as tissue destruction and fluid substance delivery, for example. The device penetrates tissue to the precise target selected in order to deliver energy to the tissue and/or deliver substances. It limits this activity to the precise preselected site, thereby minimizing trauma to normal surrounding tissue and achieving a greater medical benefit. This device is a catheter-like device for positioning a treatment assembly in the area or organ selected for medical treatment with one or more stylets in the catheter, mounted for extension from a stylet port in the side of the catheter through surrounding tissue to the tissue targeted for medical activity.
Treatment of cellular tissues usually requires direct contact of target tissue with a medical instrument, usually by surgical procedures exposing both the target and intervening tissue to substantial trauma. Often, precise placement of a treatment probe is difficult because of the location of a target tissue in the body or the proximity of the target tissue to easily damaged, critical body organs, nerves, or other components.
Benign prostatic hypertrophy or hyperplasia (BPH), for example, is one of the most common medical problems experienced by men over 50 years old. Urinary tract obstruction due to prostatic hyperplasia has been recognized since the earliest days of medicine. Hyperplastic enlargement of the prostate gland often leads to compression of the urethra, resulting in obstruction of the urinary tract and the subsequent development of symptoms including frequent urination, decrease in urinary flow, nocturia, pain, discomfort, and dribbling. The association of BPH with aging has been shown to exceed 50% in men over 50 years of age and increases in incidence to over 75% in men over 80 years of age. Symptoms of urinary obstruction occur most frequently between the ages of 65 and 70 when approximately 65% of men in this age group have prostatic enlargement.
Currently there is no proven effective nonsurgical method of treatment of BPH. In addition, the surgical procedures available are not totally satisfactory. Currently patients suffering from the obstructive symptoms of this disease are provided with few options: continue to cope with the symptoms (i.e., conservative management), submit to drug therapy at early stages, or submit to surgical intervention. More than 430,000 patients per year undergo surgery for removal of prostatic tissue in the United States. These represent less than five percent of men exhibiting clinical significant symptoms.
Those suffering from BPH are often elderly men, many with additional health problems which increase the risk of surgical procedures. Surgical procedures for the removal of prostatic tissue are associated with a number of hazards including anesthesia associated morbidity, hemorrhage, coagulopathies, pulmonary emboli and electrolyte imbalances. These procedures performed currently can also lead to cardiac complications, bladder perforation, incontinence, infection, urethral or bladder neck stricture, retention of prostatic chips, retrograde ejaculation, and infertility. Due to the extensive invasive nature of the current treatment options for obstructive uropathy, the majority of patients delay definitive treatment of their condition. This circumstance can lead to serious damage to structures secondary to the obstructive lesion in the prostate (bladder hypertrophy, hydronephrosis, dilation of the kidney pelves, etc.) which is not without significant consequences. In addition, a significant number of patients with symptoms sufficiently severe to warrant surgical intervention are poor operative risks and are poor candidates for prostatectomy. In addition, younger men suffering from BPH who do not desire to risk complications such as infertility are often forced to avoid surgical intervention. Thus the need, importance and value of improved surgical and non-surgical methods for treating BPH is unquestionable.
High-frequency currents are used in electrocautery procedures for cutting human tissue especially when a bloodless incision is desired or when the operating site is not accessible with a normal scalpel but presents an access for a thin instrument through natural body openings such as the esophagus, intestines or urethra. Examples include the removal of prostatic adenomas, bladder tumors or intestinal polyps. In such cases, the high-frequency current is fed by a surgical probe into the tissue to be cut. The resulting dissipated heat causes boiling and vaporization of the cell fluid at this point, whereupon the cell walls rupture and the tissue is separated.
Destruction of cellular tissues in situ has been used in the treatment of many diseases and medical conditions alone or as an adjunct to surgical removal procedures. It is often less traumatic than surgical procedures and may be the only alternative where other procedures are unsafe. Ablative treatment devices have the advantage of using a destructive energy which is rapidly dissipated and reduced to a non-destructive level by conduction and convection forces of circulating fluids and other natural body processes.
Microwave, radiofrequency, acoustical (ultrasound) and light energy (laser) devices, and tissue destructive substances have been used to destroy malignant, benign and other types of cells and tissues from a wide variety of anatomic sites and organs. Tissues treated include isolated carcinoma masses and, more specifically, organs such as the prostate, glandular and stromal nodules characteristic of benign prostate hyperplasia. These devices typically include a catheter or cannula which is used to carry a radiofrequency electrode or microwave antenna through a duct to the zone of treatment and apply energy diffusely through the duct wall into the surrounding tissue in all directions. Severe trauma is often sustained by the duct wall during this cellular destruction process, and some devices combine cooling systems with microwave antennas to reduce trauma to the ductal wall. For treating the prostate with these devices, for example, heat energy is delivered through the walls of the urethra into the surrounding prostate cells in an effort to kill the tissue constricting the urethra. Light energy, typically from a laser, is delivered to prostate tissue target sites by xe2x80x9cburning throughxe2x80x9d the wall of the urethra. Healthy cells of the duct wall and healthy tissue between the nodules and duct wall are also indiscriminately destroyed in the process and can cause unnecessary loss of some prostate function. Furthermore, the added cooling function of some microwave devices complicates the apparatus and requires that the device be sufficiently large to accommodate this cooling system.
Application of liquids to specific tissues for medical purposes is limited by the ability to obtain delivery without traumatizing intervening tissue and to effect a delivery limited to the specific target tissue. Localized chemotherapy, drug infusions, collagen injections, or injections of agents which are then activated by light, heat or chemicals would be greatly facilitated by a device which could conveniently and precisely place a fluid supply catheter opening at the specific target tissue.
It is the principal object of this invention to provide a device and method for penetrating tissue, through intervening tissues to the precise target tissue selected for a medical action such as tissue destruction and/or substance delivery, limiting this activity to the precise preselected site, thereby minimizing the trauma and achieving a greater medical benefit.
One principal object of this invention is to provide a device and method for tissue destruction of body tissues which delivers the therapeutic energy directly into a target tissue while minimizing effects on its surrounding tissue.
Another principal object of this invention is to provide a device and method for introducing fluid treatment agents, particularly flowable liquids, with greater precision and ease to a specific location in the body.
Another object of this invention is to provide a thermal destruction device which gives the operator more information about the temperature and other conditions created in both the tissue targeted for treatment and the surrounding tissue. In addition, it will provide more control over the physical placement of the stylet and over the parameters of the tissue destruction process.
In summary, the medical probe device of this invention comprises a catheter having a control end and a probe end. The probe end includes a stylet guide housing having at least one stylet port in a side wall thereof and guide means for directing a flexible stylet outward through the stylet port and through intervening tissue at a preselected angle to a target tissue. The housing can include an array of such ports. The preselected angle is preferably from 20xc2x0 to 160xc2x0 with the central axis of the stylet guide housing. The total catheter assembly includes one or more stylet guide lumena communicating with respective stylet ports and a stylet positioned in each of said stylet guide lumena for longitudinal movement from the respective port through intervening tissue to target tissues.
The stylet can be an electrical conductor enclosed within a non-conductive layer, the electrical conductor being an radiofrequency electrode. Preferably, the non-conductive layer is a sleeve which is axially or longitudinally moveable on the electrical conductor to expose a selected portion of the electrical conductor surface in the target tissue. The stylet can also be a microwave antenna.
In a still further embodiment, the stylet is a cannula having a longitudinal, central treatment fluid supply lumen extending therethrough, and the catheter has a treatment fluid transport lumen communicating with the treatment fluid supply lumen.
An ultrasound reflector such as a bubble or an ultrasound transducer can be embedded or otherwise attached to the probe end or a portion of the stylet to provide a signal for use in positioning the catheter and stylet.
When the stylet includes a radiofrequency electrode or microwave antenna, optimally, at least one temperature sensor such as a thermistor or fiber optic cable can be attached to the probe end, stylet guide housing and/or stylet.
In one preferred embodiment, the stylet guide defines a stylet path from an axial orientation in the catheter through a curved portion to a lateral orientation at the stylet port, the curved path optionally having a radius which is sufficient to deflect the deployed, extended stylet to the desired angle, that is, a radius of up to 0.5 cm, depending upon the diameter of the catheter. The stylet guide means can define a stylet path having a first curved portion extending in a direction away from the stylet port and a second curved portion, continuing from the first curved portion and extending to the stylet port.
For deploying a plurality of stylets, the stylet guide means can define at least two non-intersecting stylet paths from parallel axial orientations in the catheter through curved portions to lateral orientations at stylet ports, the stylet ports having axes forming an angle of up to 180xc2x0. For treating prostate lobes in one embodiment, the stylet port axes form an angle of less than 90xc2x0 and preferably from 50xc2x0 to 70xc2x0.
The non-conductive sleeve can comprise a leading tip, a rigid proximal control section, and a flexible portion extending from the leading tip the rigid proximal control section, whereby the sleeve can be extended through a curved path from an axial orientation to an orientation extending outward through a stylet port. The leading tip can be tapered inward toward its terminal end. The flexible portion can optionally be a spiral coil. If the spiral coil is made of conductive material, it can be enclosed in an outer non-conductive material.
The distal portion of the catheter can be more flexible than the proximal portion thereof, facilitating its passage through curved ducts.
In one embodiment, a control handle is attached to the control end of the catheter and stylet movement means attached to a stylet and engaging the handle for longitudinal movement of the stylet in the stylet guide means. The stylet movement means comprises manual engagement means for translating manual motion into longitudinal motion of the stylet in the stylet guide means.
In embodiments where the electrical conductor has axial movement in the non-conductive sleeve, a non-conductive sleeve movement means is attached to a non-conductive sleeve and an electrical conductor movement means is attached to the electrical conductor enclosed therein. The non-conductive sleeve movement means translates manual motion into longitudinal motion of the non-conductive sleeve in the stylet guide means. The electrical conductor movement means translates manual motion into longitudinal motion of the electrical conductor in the non-conductive sleeve. The non-conductive sleeve movement means and the electrical conductor movement means engage the handle for movement thereon. The non-conductive sleeve movement means and the electrical conductor movement means can include separate, adjacent manual movement means, mounted on the handle for both separate and coordinated movement thereon. The housing can have at least two parallel longitudinal slots through a wall thereof, the manual movement means each including a finger engaging surface connected to a slide extending through one of the longitudinal slots to a connector in the interior of the housing, the connector being attached to a respective non-conductive sleeve or electrical conductor.
The method of this invention for applying destructive energy to a target tissue comprises first introducing a catheter to a zone adjacent to the tissue to be treated. Then an electrical conductor is moved from the catheter through surrounding tissue into a target tissue to be destroyed. The electrical conductor can be a wire or tube comprising a conductive surface surrounded by a non-conductive sleeve for preventing significant transfer of energy from the conductor in tissue surrounding the sleeve. Heat is generated in the target tissue-from an electric current or electromagnetic field produced by the electrical conductor. The volume of tissue being treated is controlled by moving the non-conductive sleeve to expose a selected length of electrode in the body tissue to be treated, the remaining area of the electrode remaining shielded by the sleeve to protect the intervening tissues. The amount and duration of the energy delivery is also varied to control the volume of tissue being treated.
The electrical conductor can be positioned using a fiber optic viewing system incorporated within the catheter shaft, positioned to facilitate positioning of the device. Such a system can also include separate optics for lumination and viewing, and flushing fluid supply conduits for flushing the viewing fields.
The electrical conductor can also be positioned in the tissue to be treated using ultrasound imaging from an ultrasound transducer positioned at a distance from the target tissue or supported by the electrical conductor or non-conducting sleeve.
The extent of heating can be monitored and controlled during the ablative treatment using temperature sensors supported by the electrical conductor or non-conductive sleeve.
In another embodiment of the method of this invention for treating a target tissue such as the prostate, two flexible stylets from the catheter are moved through catheter ports in the sidewall of the catheter and through the urethra wall and surrounding tissue into the prostate target tissue to be treated, the catheter ports having axes forming an angle of less than 180xc2x0 and for treatment in some tissue, less than 90xc2x0.
In a still further embodiment, a grounding plate is placed on the skin to direct the electrical current passing from one or more electrodes in a path through the target tissue to be ablated.